Camera module

ABSTRACT

A camera module includes a housing accommodating a lens module, a driving unit including a magnet disposed on the lens module and a coil disposed to face the magnet, a yoke generating attractive force with the magnet, a first ball member accommodated in a first receiving space disposed between the lens module and the housing, and pressed by the attractive force, and a second ball member accommodated in a second receiving space disposed between the lens module and the housing, and pressed by the attractive force. A length of the first receiving space in an optical axis direction is different from a length of the second receiving space in the optical axis direction.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.16/365,986 filed on Mar. 27, 2019, which claims the benefit of 35 U.S.C.§ 119(a) of Korean Patent Application No. 10-2018-0091939 filed on Aug.7, 2018 in the Korean Intellectual Property Office, the entiredisclosures of which are incorporated herein by reference for allpurposes.

BACKGROUND 1. Field

The following description relates to a camera module.

2. Description of Background

Camera modules have been used in mobile communications terminals such assmartphones, tablet PCs, notebook computers, and the like. Such cameramodules have a focus adjustment function for generating high-resolutionimages.

When the focus is adjusted, a lens module is moved in an optical axisdirection by an actuator. When the lens module is moved, a plurality ofball bearings and the like may be used to support the movement of thelens module in the optical axis direction. The plurality of ballbearings may contact the lens module and roll in the optical axisdirection to support the lens module.

The plurality of ball bearings need to contact and support the lensmodule. However, it may be significantly difficult to make the sizes ofthe plurality of ball bearings exactly the same in a manufacturingprocess. Thus, the sizes of the plurality of ball bearings may bedifferent from each other.

In the case in which there is a slight difference in the size of theplurality of ball bearings, only portions of the ball bearings may comein contact with the lens module, which may cause tilt when the lensmodule is moved in the optical axis direction.

Furthermore, in a process in which the lens module is moved in anoptical axis direction, the ball bearings contacting the lens module maybe changed, thereby causing a continuous tilt phenomenon in which thelens module tilts.

Further, since the size difference between the plurality of ballbearings is difficult to visually determine, there may be a problem inthat it may be difficult to predict which of the plurality of balls willcontact the lens module.

Moving a lens module in parallel in an optical axis direction may bevery important in focus adjustment. Therefore, it is necessary toprevent tilt from occurring when the lens module moves.

Meanwhile, the size of a camera module used in a mobile communicationsterminal has gradually been reduced. As the size of the camera modulehas been reduced, the problem of resolution degradation due to lensmodule tilt has increased.

SUMMARY

This Summary is provided to introduce a selection of concepts insimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used as an aid in determining the scope of the claimed subjectmatter.

In one general aspect, a camera module in which tilt may be preventedfrom occurring when a lens module is moved in an optical axis direction.

In another general aspect, a camera module includes a housingaccommodating a lens module; a driving unit including a magnet disposedon the lens module and a coil disposed to face the magnet; a yokegenerating attractive force with the magnet; a first ball memberaccommodated in a first receiving space disposed between the lens moduleand the housing, and pressed by the attractive force; and a second ballmember accommodated in a second receiving space disposed between thelens module and the housing, and pressed by the attractive force. Alength of the first receiving space in an optical axis direction isdifferent from a length of the second receiving space in the opticalaxis direction.

The first ball member may include first balls disposed in the opticalaxis direction and the second ball member may include second ballsdisposed in the optical axis direction, and at least two of the firstballs may have differing sizes.

A number of the first balls may be different from a number of the secondballs.

An uppermost ball and a lowermost ball in the optical axis direction,among the first balls, may be greater in size than at least one balllocated between the uppermost ball and the lowermost ball, and thesecond balls may have sizes corresponding to each other.

A first uppermost ball and a first lowermost ball in the optical axisdirection, among the first balls, may be greater in size than at leastone ball located between the first uppermost ball and the firstlowermost ball, and a second uppermost ball and a second lowermost ballin the optical axis direction, among the second balls, may be greater insize than at least one ball located between the second uppermost balland the second lowermost ball.

The camera module may include a case coupled to the housing to encloseat least a portion of an outer surface of the housing.

The housing may include a first protrusion protruding toward the firstball member and a second protrusion protruding toward the second ballmember.

A length of the first protrusion may be different from a length of thesecond protrusion in the optical axis direction.

The case may include a third protrusion protruding toward the first ballmember and a fourth protrusion protruding toward the second ball member.

A length of the third protrusion may be different from a length of thefourth protrusion in the optical axis direction.

In another general aspect, a camera module includes a housingaccommodating a lens module; a driving unit including a magnet disposedon the lens module and a coil disposed to face the magnet; a yokegenerating attractive force with the magnet; a first ball memberdisposed between the lens module and the housing and pressed by theattractive force, and including first balls arranged in an optical axisdirection; and a second ball member disposed between the lens module andthe housing, and pressed by the attractive force, and including secondballs arranged in the optical axis direction. A first distance between acenter of a first uppermost ball and a center of a first lowermost ballin the optical axis direction, among the first balls, is different froma second distance between a center of a second uppermost ball and acenter of a second lowermost ball, among the second balls.

A number of the first balls may be different from a number of the secondballs, the first uppermost ball and the first lowermost ball may begreater in size than at least one ball located between the firstuppermost ball and the first lowermost ball, and the second uppermostball and the second lowermost ball may be greater in size than at leastone ball located between the second uppermost ball and the secondlowermost ball.

A number of the first balls may be different from a number of the secondballs, the first uppermost ball and the first lowermost ball may begreater in size than at least one ball located between the firstuppermost ball and the first lowermost ball, and the second balls mayhave sizes corresponding to each other.

The second lowermost ball may be disposed higher than the firstlowermost ball in the optical axis direction.

The second uppermost ball may be disposed lower than the first uppermostball in the optical axis direction.

In another general aspect, a camera module includes a housing includinga first receiving groove and a second receiving groove; a lens moduleaccommodated in the housing and including a third receiving groovefacing the first receiving groove and a fourth receiving groove facingthe second receiving groove; first ball bearings disposed is a firstspace defined by the first receiving groove and the third receivinggroove; and second ball bearings disposed is a second space defined bythe second receiving groove and the fourth receiving groove. The housingincludes a first protrusion protruding into the first space and a secondprotrusion protruding into the second space, and a length of the firstprotrusion in an optical axis direction is different from a length ofthe second protrusion in the optical axis direction.

The lens module may include a third protrusion protruding into the firstspace and a fourth protrusion protruding into the second space, and alength of the third protrusion in the optical axis direction may bedifferent from a length of the fourth protrusion in the optical axisdirection.

A length of the first space in the optical axis direction may bedifferent from a length of the second space in the optical axisdirection.

Other features and aspects will be apparent from the following detaileddescription, the drawings, and the claims.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view illustrating an example of a camera module.

FIG. 2 is a schematic exploded perspective view illustrating an exampleof a camera module.

FIG. 3 is a view illustrating a case in which tilt occurs duringmovement of a lens module.

FIG. 4 is a cross-sectional view taken along line I-I′ of FIG. 1 .

FIG. 5 is a modified example of FIG. 4 .

FIG. 6 is another modified example of FIG. 4 .

FIG. 7 is a perspective view illustrating an example of a housing.

Throughout the drawings and the detailed description, the same referencenumerals refer to the same elements. The drawings may not be to scale,and the relative size, proportions, and depiction of elements in thedrawings may be exaggerated for clarity, illustration, and convenience.

DETAILED DESCRIPTION

The following detailed description is provided to assist the reader ingaining a comprehensive understanding of the methods, apparatuses,and/or systems described herein. However, various changes,modifications, and equivalents of the methods, apparatuses, and/orsystems described herein will be apparent after gaining an understandingof the disclosure of this application. For example, the sequences ofoperations described herein are merely examples, and are not limited tothose set forth herein, but may be changed, as will be apparent aftergaining an understanding of the disclosure of this application, with theexception of operations necessarily occurring in a certain order. Also,descriptions of features that are known in the art may be omitted forincreased clarity and conciseness.

The features described herein may be embodied in different forms, andare not to be construed as being limited to the examples describedherein. Rather, the examples described herein have merely been providedto illustrate some of the many possible ways of implementing themethods, apparatuses, and/or systems described herein that will beapparent after an understanding of the disclosure of this application.

Throughout the specification, when an element, such as a layer, region,or substrate, is described as being “on,” “connected to,” or “coupledto” another element, it may be directly “on,” “connected to,” or“coupled to” the other element, or there may be one or more otherelements intervening therebetween. In contrast, when an element isdescribed as being “directly on,” “directly connected to,” or “directlycoupled to” another element, there may be no other elements interveningtherebetween.

The terminology used herein is for describing various examples only, andis not to be used to limit the disclosure. As used herein, the term“and/or” includes any one and any combination of any two or more of theassociated listed items. The articles “a,” “an,” and “the” are intendedto include the plural forms as well, unless the context clearlyindicates otherwise.

The use of the term “may” with respect to an example or embodiment,e.g., as to what an example or embodiment may include or implement,means that at least one example or embodiment exists in which such afeature is included or implemented while all examples and embodimentsare not limited thereto.

Although terms such as “first,” “second,” and “third” may be used hereinto describe various members, components, regions, layers, or sections,these members, components, regions, layers, or sections are not to belimited by these terms. Rather, these terms are only used to distinguishone member, component, region, layer, or section from another member,component, region, layer, or section. Thus, a first member, component,region, layer, or section referred to in examples described herein mayalso be referred to as a second member, component, region, layer, orsection without departing from the teachings of the examples.

Spatially relative terms such as “above,” “upper,” “below,” and “lower”may be used herein for ease of description to describe one element'srelationship to another element as shown in the figures. Such spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. For example, if the device in the figures is turned over,an element described as being “above” or “upper” relative to anotherelement will then be “below” or “lower,” relative to the other element.Thus, the term “above” encompasses both the above and below orientationsdepending on the spatial orientation of the device. The device may alsobe oriented in other ways (for example, rotated 90 degrees or at otherorientations), and the spatially relative terms used herein are to beinterpreted accordingly.

Due to manufacturing techniques and/or tolerances, variations of theshapes shown in the drawings may occur. Thus, the examples describedherein are not limited to the specific shapes shown in the drawings, butinclude changes in shape that occur during manufacturing.

The camera module may be applied to portable electronic devices such asa mobile communications terminal, a smart phone, a tablet PC or thelike.

FIG. 1 is a perspective view illustrating an example of a camera module,and FIG. 2 is a schematic exploded perspective view illustrating anexample of the camera module.

Referring to FIGS. 1 and 2 , a camera module includes a lens module 200,a driving unit 300 moving the lens module 200, an image sensor module500 converting light incident through the lens module 200 into anelectrical signal, and a housing 400 and a case 100 receiving the lensmodule 200.

The lens module 200 includes a lens barrel 210 and a carrier 230.

The lens barrel 210 may receive at least one lens capturing an object.When a plurality of lenses are disposed, the plurality of lenses aremounted inside the lens barrel 210 along an optical axis. The lensbarrel 210 may have a hollow cylindrical shape.

The lens barrel 210 is coupled to the carrier 230, and the lens barrel210 and the carrier 230 are housed in the housing 400 and the case 100.The case 100 is coupled to the housing 400 to surround an outer surfaceof the housing 400.

The lens barrel 210 is configured to be movable together with thecarrier 230 in the direction of an optical axis.

For example, the lens module 200 may be moved in the optical axisdirection to adjust a focus, and the driving unit 300 is provided tomove the lens module 200.

The image sensor module 500 is disposed below the housing 400. The imagesensor module 500 converts light incident through the lens module 200into an electric signal.

The image sensor module 500 may include an image sensor 510, and aprinted circuit board 530 connected to the image sensor 510, and mayfurther include an infrared filter.

The infrared filter functions to block light in an infrared region, inthe light incident through the lens module 200.

The image sensor 510 converts the light incident through the lens barrel210 into an electric signal. In an example, the image sensor 510 may bea charge coupled device (CCD) or a complementary metal-oxidesemiconductor (CMOS).

The electric signal converted by the image sensor 510 is output as animage through a display unit of a portable electronic device.

The image sensor 510 is fixed to the printed circuit board 530, and iselectrically connected to the printed circuit board 530 by wire bonding.

The driving unit 300 includes a magnet 310 and a coil 320. The magnet310 may be provided in the lens module 200, and the coil 320 may bedisposed to face the magnet 310.

In an example, the magnet 310 may be mounted on one surface of thecarrier 230, and the coil 320 may be provided on one surface of asubstrate 330 mounted in the housing 400. The magnet 310 and the coil320 may be disposed to face each other in a direction perpendicular tothe optical axis direction.

When power is applied to the coil 320, the carrier 230 may be moved inthe optical axis direction by influence of electromagnetic force betweenthe magnet 310 and the coil 320.

Since the lens barrel 210 is mounted in the carrier 230, the lens barrel210 is also moved in the optical axis direction by movement of thecarrier 230.

A first ball member 600 and a second ball member 700 may be disposedbetween the lens module 200 and the housing 400, to reduce frictionbetween the lens module 200 and the housing 400, when the lens module200 is moved in the optical axis direction.

A first receiving space is formed between the lens module 200 and thehousing 400, and the first ball member 600 is accommodated in the firstreceiving space. A second receiving space is also formed between thelens module 200 and the housing 400, and the second ball member 700 isaccommodated in the second receiving space.

The housing 400 is provided with a first receiving groove 410 and asecond receiving groove 430, and the lens module 200 is provided with athird receiving groove 231 and a fourth receiving groove 233. Each ofthe first receiving groove 410, the second receiving groove 430, thethird receiving groove 231, and the fourth receiving groove 233 extendto have a length in an optical axis direction.

The first receiving groove 410 and the third receiving groove 231 aredisposed to face each other in a direction perpendicular to the opticalaxis direction, and a space between the first receiving groove 410 andthe third receiving groove 231 functions as the first receiving spacefor accommodating the first ball member 600. The second receiving groove430 and the fourth receiving groove 233 are disposed to face each otherin the direction perpendicular to the optical axis direction, and aspace between the second receiving groove 430 and the fourth receivinggroove 233 functions as the second receiving space for accommodating thesecond ball member 700.

The first ball member 600 is disposed between the first receiving groove410 and the third receiving groove 231, and the second ball member 700is disposed between the second receiving groove 430 and the fourthreceiving groove 233.

The first receiving groove 410, the second receiving groove 430, and thethird receiving groove 231 have a substantially ‘v’-shaped crosssection, and the fourth receiving groove 233 has a substantially‘¬’-shaped cross section.

Thus, the first ball member 600 may be in two-point contact with thefirst receiving groove 410, and may also be in two-point contact withthe third receiving groove 231. The second ball member 700 may be intwo-point contact with the second receiving groove 430, and may be inone-point contact with the fourth receiving groove 233.

For example, the first ball member 600 may be in four-point contact withan object, and the second ball member 700 may be in three-point contactwith the object.

The first ball member 600 accommodated in the first receiving spacebetween the first receiving groove 410 and the third receiving groove231 may function as a main guide, and the second ball member 700accommodated in the second receiving space between the second receivinggroove 430 and the fourth receiving groove 233 may function as anauxiliary guide.

In an example, a closed loop control method of detecting and feedingback a position of the lens module 200 is used.

Thus, a position detector 350 is provided for closed loop control. Theposition detector 350 may be a Hall sensor, and may be disposed in acentral portion of the coil 320. The position detector 350 may be formedintegrally with a driver IC, applying power to the coil 320.

A yoke 340 is disposed on the other surface of the substrate 330(opposite surface of the substrate 330 from the coil 320/detector 350).Thus, the yoke 340 is disposed to face the magnet 310 in a directionperpendicular to the optical axis direction, with the coil 320interposed between the yoke 340 and the magnet 310.

The yoke 340 is formed of a material capable of generating attractiveforce between the yoke 340 and the magnet 310, such that attraction maybe exerted between the yoke 340 and the magnet 310 in a directionperpendicular to the optical axis direction.

The first ball member 600 and the second ball member 700 are pressed bythe attractive force between the yoke 340 and the magnet 310, in such amanner that the first ball member 600 and the second ball member 700 maymaintain contact with the lens module 200 and the housing 400.

FIG. 3 is a view illustrating a case in which tilt occurs duringmovement of a lens module, and FIG. 4 is a cross-sectional view takenalong line I-I′ of FIG. 1 .

FIG. 5 is a modified example of FIG. 4 , and FIG. 6 is another modifiedexample of FIG. 4 .

FIG. 7 is a perspective view illustrating an example of a housing.

Referring to FIG. 3 , in the case of a general camera module capable ofadjusting focus, a plurality of ball bearings B1 and B2 are disposed,respectively on both sides of a magnet M.

A yoke is disposed to face the magnet M in a direction perpendicular toan optical axis direction. The yoke is a fixing member and the magnet Mis a moving member, such that the magnet M is pulled toward the yoke byattractive force acting between the magnet M and the yoke. Thus, a lensmodule L on which the magnet M is mounted is also pulled toward theyoke.

Thus, the plurality of ball bearings B1 and B2 are brought into contactwith the lens module L and a housing H, by the attractive force betweenthe magnet M and the yoke. In this state, the plurality of ball bearingsB1 and B2 support the lens module L when the lens module L is moved inthe optical axis direction.

When the sizes of the plurality of ball bearings B1 and B2 are all thesame, all the ball bearings contact the lens module L, so that the lensmodule L may be stably supported.

For example, as illustrated in FIG. 3 , in the case in whichrespectively three ball bearings B1 and B2 disposed on both sides of themagnet M are all in contact with the lens module L and the housing H,the lens module L may be stably supported.

However, it is relatively very difficult to physically make the sizes ofthe plurality of ball bearings B1 and B2 completely equal. Thus, evenwhen the sizes of the plurality of ball bearings B1 and B2 are all madethe same, the sizes of the plurality of actually manufactured ballbearings B1 and B2 may be different from each other.

As described above, in the case in which there is a slight difference inthe size of the plurality of ball bearings B1 and B2, only a portion ofball bearings comes into contact with the lens module L, and thus, tiltmay occur when the lens module L is moved in the optical axis direction.

To prevent tilt from occurring in a process of moving the lens module L,a center point C of action of attractive force acting between the magnetM and the yoke is required to be located within a support region Aprovided by connecting points of contact between the plurality of ballbearings B1 and B2 and the lens module L or the housing H.

However, in a case in which only portions of the plurality of ballbearings B1 and B2 contact the lens module L, the center point C ofaction of the attractive force may be located in a region deviating fromthe support region A during movement of the lens module L.

In this case, a position of the lens module L may be changed during themovement of the lens module L, which may cause tilt.

Referring to FIG. 4 , the first ball member 600 and the second ballmember 700 are disposed on both sides of the magnet 310, and each of thefirst ball member 600 and the second ball member 700 includes aplurality of balls disposed in the optical axis direction.

In the case of a camera module according to an example, a size, forexample, a diameter, of a portion of a plurality of balls may beintentionally formed to be greater than a size, for example, a diameter,of remaining balls. In this case, relatively large balls, among theplurality of balls, may intentionally contact the lens module 200.

For example, the size of uppermost balls and lowermost balls among theplurality of balls in an optical axis direction may be greater than thesize of balls located between the respective uppermost balls andlowermost balls.

Among the plurality of balls of the first ball member 600, an uppermostball 610 and a lowermost ball 630 in the optical axis direction aregreater in size (for example, greater in diameter) than a ball 620located between the uppermost ball 610 and the lowermost ball 630. Balls710 and 720 of the second ball member 700 have sizes corresponding(relatively equal) to each other.

The uppermost ball 610 and the lowermost ball 630 among the plurality ofballs of the first ball member 600 in the optical axis direction, andthe balls 710 and 720 of the second ball member 700, may have sizescorresponding (relatively equal) to each other.

The number of balls of the first ball member 600 and the number of ballsof the second ball member 700 are different. For example, the number ofballs of the first ball member 600 is greater than the number of ballsof the second ball member 700. In this example, the first ball member600 includes three balls (610, 620, and 630), and the second ball member700 includes two balls (710 and 720).

In the case of the first ball member 600, the uppermost ball 610 and thelowermost ball 630 contact the lens module 200, and in the case of thesecond ball member 700, both balls 710 and 720 come into contact withthe lens module 200, for example at four support points.

In this case, a support region SA, connecting the contact points betweenthe first ball member 600 and the lens module 200 and the contact pointsbetween the second ball member 700 and the lens module 200, may have arectangular shape, for example, a trapezoidal shape.

Thus, by intentionally contacting portions of the balls with the lensmodule 200, the center portion of action of attractive force between themagnet 310 and the yoke 340 may be located in the support region SA,connecting points of contact between portions of the balls and the lensmodule 200.

Even when the uppermost ball 610 and the lowermost ball 630 among theballs of the first ball member 600, and the balls 710 and 720 of thesecond ball member 700, are formed to have corresponding sizes to eachother, the sizes thereof after manufacture may be different from eachother.

In this case, the uppermost ball 610 and the lowermost ball 630 amongthe balls of the first ball member 600 may be in contact with the lensmodule 200, and only one of the balls of the second ball member 700 maybe in contact with the lens module 200, for example, at three supportpoints.

In this case, the support region SA, connecting the contact pointsbetween the first ball member 600 and the lens module 200 and thecontact points between the second ball member 700 and the lens module200, may have a triangular shape. Thus, the support region SA may bereduced, as compared with the case of four-point support.

However, in the case of the disclosed examples, the center point C ofaction of the attractive force between the magnet 310 and the yoke 340may be positioned in the support region SA even when the support regionSA is triangular.

In an example, a size of the first receiving space in the optical axisdirection, in which the first ball member 600 is accommodated, and asize of the second receiving space in the optical axis direction, inwhich the second ball member 700 is accommodated, may be formed to bedifferent from each other.

For example, the size of the first receiving space in the optical axisdirection may be greater than the size of the second receiving space inthe optical axis direction.

Thus, a distance D1 between centers of the uppermost ball 610 and thelowermost ball 630 of the first ball member 600 in the optical axisdirection accommodated in the first receiving space, is different from adistance D2 between centers of the uppermost ball 710 and the lowermostball 720 in the optical axis direction, among the balls of the secondball member 700 accommodated in the second receiving space.

For example, the distance D1 between the centers of the uppermost ball610 and the lowermost ball 630 in the optical axis direction, among theballs of the first ball member 600 accommodated in the first receivingspace, is greater than the distance D2 between the centers of theuppermost ball 710 and the lowermost ball 720 in the optical axisdirection, among the balls of the second ball member 700 accommodated inthe second receiving space.

The housing 400 includes a first protrusion 411 protruding toward thefirst ball member 600, and a second protrusion 431 protruding toward thesecond ball member 700.

The first protrusion 411 and the second protrusion 431 have differentlengths in the optical axis direction. For example, the length of thesecond protrusion 431 in the optical axis direction is greater than thelength of the first protrusion 411 in the optical axis direction.

As illustrated in FIG. 4 , the lowermost ball 720 among the balls of thesecond ball member 700 in the optical axis direction is disposed to behigher than the lowermost ball 630 among the balls of the first ballmember 600 in the optical axis direction, when viewed in a directionperpendicular to the optical axis direction.

Thus, even when the support region SA connecting the contact pointsbetween the first ball member 600 and the lens module 200 and thecontact points between the second ball member 700 and the lens module200 has a triangular shape, angles formed by respective sides of atriangle may all be acute.

Therefore, even when the support region SA is triangular, since thecenter point C of action of the attractive force between the magnet 310and the yoke 340 may be located within the support region SA, tilt maybe effectively prevented from occurring during a movement process of thelens module 200.

The case 100 is provided with a third protrusion 110 protruding towardthe first ball member 600 and a fourth protrusion 120 protruding towardthe second ball member 700.

In this case, the third protrusion 110 and the fourth protrusion 120have different lengths in the optical axis direction. For example, thelength of the fourth protrusion 120 in the optical axis direction isgreater than the length of the third protrusion 110 in the optical axisdirection.

As illustrated in FIG. 4 , the uppermost ball 710 among the balls of thesecond ball member 700 in the optical axis direction is disposed to belower than the uppermost ball 610 among the balls of the first ballmember 600 in the optical axis direction, when viewed in a directionperpendicular to the optical axis.

Therefore, even when the support region SA connecting the contact pointsbetween the first ball member 600 and the lens module 200 and thecontact points between the second ball member 700 and the lens module200 has a triangular shape, angles formed by respective sides of atriangle may all be acute.

Therefore, even when the support region SA is triangular, since thecenter point C of action of the attractive force between the magnet 310and the yoke 340 may be located within the support region SA, tilt maybe effectively prevented from occurring during a movement process of thelens module 200.

Referring to FIG. 5 , in another example, a first ball member 600′ mayinclude four balls, and a second ball member 700 may include two balls.

Among the four balls of the first ball member 600′, uppermost andlowermost balls 610′ and 640′ in an optical axis direction are greaterin size (for example, greater in diameter) than balls 620′ and 630′located between the uppermost and lowermost balls 610′ and 640′.

Thus, even in a case in which a support region SA, connecting contactpoints between the first ball member 600′ and the lens module 200 andcontact points between the second ball member 700 and the lens module200, has a rectangular shape or a triangular shape, since angles formedby respective sides of a triangle may all be acute, a center point C ofaction of attractive force between a magnet 310 and a yoke 340 may bewithin the support region SA.

Referring to FIG. 6 , in another example, a first ball member 600′ mayinclude four balls, and a second ball member 700′ may include threeballs.

Among the four balls of the first ball member 600′, uppermost andlowermost balls 610′ and 640′ in an optical axis direction are greaterin size (for example, greater in diameter) than balls 620′ and 630′located between the uppermost and lowermost balls 610′ and 640′, andamong the three balls of the second ball member 700′, uppermost andlowermost balls 710′ and 730′ in an optical axis direction are greaterin size (for example, greater in diameter) than a ball 720′ locatedbetween the uppermost and lowermost balls 710′ and 730′.

Thus, even in a case in which a support region SA, connecting contactpoints between the first ball member 600′ and the lens module 200 andcontact points between the second ball member 700′ and the lens module200, has a rectangular shape or a triangular shape, since angles formedby respective sides of a triangle may all be acute, a center point C ofaction of attractive force between a magnet 310 and a yoke 340 may bewithin the support region SA.

FIG. 7 illustrates an example of the housing 400, as described withrespect to FIG. 4 . The housing 400 includes the first protrusion 411protruding therefrom, and the first protrusion 411 defines a lower endof the first receiving groove 410. The housing 400 also includes thesecond protrusion 431 protruding therefrom, and the second protrusion431 defines a lower end of the second receiving groove 430. As discussedabove, a length of the second protrusion 431 in the optical axisdirection may be greater than a length of the first protrusion 411 inthe optical axis direction.

Through the above-described examples, the camera module according to theexample of the present disclosure may prevent tilt from occurring whenthe lens module is moved in the optical axis direction.

As set forth above, a camera module according to the examples mayprevent tilt occurring when a lens module is moved in an optical axisdirection.

While this disclosure includes specific examples, it will be apparentafter an understanding of the disclosure of this application thatvarious changes in form and details may be made in these exampleswithout departing from the spirit and scope of the claims and theirequivalents. The examples described herein are to be considered in adescriptive sense only, and not for purposes of limitation. Descriptionsof features or aspects of the present disclosure in each example are tobe considered as being applicable to similar features or aspects of thepresent disclosure in other examples. Suitable results may be achievedif the described techniques are performed in a different order, and/orif components in a described system, architecture, device, or circuitare combined in a different manner, and/or replaced or supplemented byother components or their equivalents. Therefore, the scope of thedisclosure is defined not by the detailed description, but by the claimsand their equivalents, and all variations within the scope of the claimsand their equivalents are to be construed as being included in thedisclosure.

What is claimed is:
 1. A camera module comprising: a housingaccommodating a lens module; a driving unit comprising a magnet disposedon the lens module and a coil disposed to face the magnet; a yokedisposed to face the magnet; a first ball member disposed between thelens module and the housing; and a second ball member disposed betweenthe lens module and the housing, wherein the housing comprises a firstprotrusion protruding toward the first ball member and a secondprotrusion protruding toward the second ban member, and wherein a lengthof the first protrusion is different from a length of the secondprotrusion in an optical axis direction.
 2. The camera module of claim1, wherein the first ball member comprises first balls disposed in theoptical axis direction and the second ball member comprises second ballsdisposed in the optical axis direction, and a number of the first ballsis different from a number of the second balls.
 3. The camera module ofclaim 2, wherein the number of the first balls is greater than thenumber of the second balls.
 4. The camera module of claim 3, wherein anuppermost ball and a lowermost ball in the optical axis direction, amongthe first balls, are greater in size than at least one ball locatedbetween the uppermost ball and the lowermost ball.
 5. The camera moduleof claim 3, wherein a first uppermost ball and a first lowermost ball inthe optical axis direction, among the first balls, are greater in sizethan at least one ball located between the first uppermost ball and thefirst lowermost ball, and a second uppermost ball and a second lowermostball in the optical axis direction, among the second balls, are greaterin size than at least one ball located between the second uppermost balland the second lowermost ball.
 6. The camera module of claim 1, whereinthe length of the first protrusion is shorter than the length of thesecond protrusion in the optical axis direction.
 7. The camera module ofclaim 1, further comprising a case coupled to the housing.
 8. The cameramodule of claim 7, wherein the case comprises a third protrusionprotruding toward the first ball member and a fourth protrusionprotruding toward the second ball member.
 9. The camera module of claim8, wherein a length of the third protrusion is different from a lengthof the fourth protrusion in the optical axis direction.
 10. A cameramodule comprising: a housing accommodating a lens module; a driving unitcomprising a magnet disposed on the lens module and a coil disposed toface the magnet; a first ball member disposed between the lens moduleand the housing, and comprising first balls arranged in an optical axisdirection; and a second ball member disposed between the lens module andthe housing, and comprising second balls arranged in the optical axisdirection, wherein a first distance between a center of a firstuppermost ball and a center of a first lowermost ball in the opticalaxis direction, among the first balls, is different from a seconddistance between a center of a second uppermost ball and a center of asecond lowermost ball in the optical axis direction, among the secondballs, wherein the housing comprises a first protrusion protrudingtoward the first ball member and a second protrusion protruding towardthe second ball member, and wherein a length of the first protrusion isdifferent from a length of the second protrusion in an optical axisdirection.
 11. The camera module of claim 10, wherein a number of thefirst balls is greater than a number of the second balls, the firstuppermost ball and the first lowermost ball are greater in size than atleast one ball located between the first uppermost ball and the firstlowermost ball.
 12. The camera module of claim 10, further comprising ayoke disposed to face the magnet.
 13. The camera module of claim 10,wherein the second lowermost ball is disposed higher than the firstlowermost ball in the optical axis direction.
 14. The camera module ofclaim 10, wherein the second uppermost ball is disposed lower than thefirst uppermost ball in the optical axis direction.
 15. The cameramodule of claim 10, further comprising a case coupled to the housing,wherein the case comprises a third protrusion protruding toward thefirst ball member and a fourth protrusion protruding toward the secondball member, and a length of the third protrusion in the optical axisdirection is different from a length of the fourth protrusion in theoptical axis direction.
 16. A camera module comprising: a housingcoupled to a case to define an accommodating space configured toaccommodate a lens module; first protrusions disposed in a firstreceiving space between the lens module and the housing; secondprotrusions disposed in a second receiving space, different from thefirst receiving space, between the lens module and the housing, whereinthe first and second protrusions extend in an optical axis direction; afirst ball member disposed in the first receiving space; a second ballmember disposed in second receiving space; and a driving unit,accommodated within the housing, configured to move the lens module inthe optical axis direction.